JPH027263Y2 - - Google Patents

Description

[Detailed explanation of the idea]

[Industrial Application Field] This invention relates to an internal reduction starter incorporating a planetary gear. [Prior Art] Fig. 5 shows a conventional planetary gear reduction mechanism and its buffer mechanism disclosed in, for example, Japanese Utility Model Application Publication No. 59-97262. A support pin 3 is an internal gear with which the planetary gear 2 is internally meshed; 4 is a corrugated and cylindrical buffer material; They are alternately engaged with grooves 7 provided on the outer periphery of the grooves 7. 8 is a sun gear, which is provided on the motor shaft. Next, the operation of the above configuration will be explained. The sun gear 8 is driven by a motor (not shown), the planetary gears 2 are rotationally biased and revolve around the inner peripheral surface of the internal gear 3 in the same direction, and the support pin 1 is also rotationally biased. The rotational force is transmitted to the arm to which the engine is fixed and the rotating shaft (both not shown) to which the arm is fixed, and the engine is started. If there is a sudden change in rotational force during engine cranking (rotational energization) or engine stalling, the buffer material 4 will elastically deform and absorb the impact load generated on the reduction gear, resulting in gear breakage. can be prevented. [Problems to be solved by the invention] Since the conventional planetary gear reduction mechanism and its buffer mechanism are constructed as described above, the structure of the buffer material is complicated and expensive, and the hoops that occur in the internal gear 3 The structure is insufficient to absorb deformation due to stress (deformation that spreads to the outer periphery), and for example, when internal gears are made of resin molded material with a restricted external shape, there are problems such as insufficient strength. This idea was made to solve the above problems, and it is a planetary gear that can absorb the slow impact rotational force (torque) generated in the planetary gear reduction device and increase the strength of the internal gear. The purpose is to provide an internal reduction starter with a built-in. [Means for solving the problem] The internal reduction starter with a built-in planetary gear according to this invention has an internal gear formed of a resin molded material,
It is non-rotatably fitted to the machine frame via an elastic material, and
An annular space is formed between the opening of the internal gear and the inner circumferential surface of the machine frame, and an annular elastic material (relatively hard rubber) integrally formed with the above-mentioned elastic material is press-fitted into the internal gear. The internal gear is configured with a hollowed part and a rib shape to prevent deformation of the gear due to mold sinkage. [Function] The planetary gear device of this invention absorbs the impact rotational force generated in the device due to the engagement of the internal gear with the machine frame by the elastic material, and the annular portion of the elastic material absorbs the impact rotational force generated in the device by the engagement of the internal gear with the machine frame. This elastically absorbs the hoop stress and prevents gear damage. [Embodiment of the invention] An embodiment of the invention will be described below with reference to the drawings. In Figure 1, 9 is a planetary gear (planetary gear) 2
10 is a front machine frame made of an aluminum alloy die-cast material, 11 is an internal gear device made of a resin molding material (for example, nylon resin containing a glass base material is used),
A rib 12 and a protrusion 13 are provided on the outer periphery of the internal gear 11a, and are provided opposite to a protrusion 14 and a groove 15 provided on the inner peripheral surface of the front machine frame 10. 16
are columnar spaces constructed as described above, and are formed at multiple locations on the circumference. Further, FIGS. 2 to 4 showing cross sections will be explained. First, in FIG. 2, which shows a cross-sectional view taken along the line - in FIG.
is an elastic material made of a molded material of synthetic rubber, and the protrusion 18 is fitted into the columnar space 16. 1
9 is a flange into which the support pin 1 is fitted; 20 is an output rotating shaft integrally formed with this flange 19; Bearing bearing. 23 is a helical spline to which an overrunning latch (not shown) is spline-fitted so as to be slidable back and forth; 24 is a sleeve bearing fitted to the planetary gear 2, and is supported by the support pin 1 in a loosely fitted state. Reference numeral 25 denotes a motor shaft, on which a sun gear 8 is formed at the front, and a front end bearing portion 26 is rotated by a sleeve bearing 28 fitted in a groove 27 provided at the rear end of the output rotating shaft 20. Freely supported on the shaft. A steel ball 29 is interposed between the output rotating shaft 20 and the motor shaft 25, and receives a thrust load. Next, in FIG. 3, which shows a sectional view taken along the line 1 in FIG. The outer peripheral surface of the internal gear device 11 is held in a manner that reinforces the outer circumferential surface of the internal gear device 11. 17a is an annular connecting portion of the elastic member 17, which protects the end surface of the internal gear 11a. FIG. 4, which is a sectional view taken along the line N--N in FIG. 1, shows the cross-sectional shape of the protrusion 13, which has a groove 32 to prevent deformation of the internal gear 11a due to sink marks during resin molding. Note that the rib 1 of the internal gear device 11
2 is constructed such that the circumferential width A (shown in FIG. 1) is smaller than the radial width B (shown in FIG. 2) of the rim portion 11b of the internal gear device 11, that is, the relationship A<B. This prevents deformation of the internal gear 11a due to sink marks. Reference numeral 33 denotes a screw hole provided in the front machine frame 10, into which a through bolt (not shown) for screwing a DC motor (not shown) is inserted. According to the above configuration, the rotation force reaction force and impact load of the planetary gear 2 generated in the internal gear device 11 are received by the protrusion 18 fitted in the columnar space 16, and the annular part 30 receives the impact load. The opening portion (particularly easily deformable portion) of the rim portion 11b of the internal gear device 11 is elastically bound and held to prevent damage (missing) of the internal gear 11a. Furthermore, it has been confirmed through experiments that the breaking strength of the internal gear 11a differs depending on the difference in rubber hardness of the elastic material 17, as shown in Table 1.

[Effect of idea]

As described above, according to this invention, the outer circumferential surface of the internal gear made of a resin member and the machine frame are elastically screwed together via an elastic material, and the opening is covered with an annular elastic material. Since the machine frame is designed to receive pressure on the outer circumferential surface, the strength of the device against shock loads is significantly increased, noise during rotation is reduced, internal reduction type starters can be made at low cost, and they are highly accurate. It has the effect of getting something.

[Brief explanation of the drawing]

FIG. 1 is an exploded side view showing the main parts of an internal reduction starter incorporating a planetary gear according to an embodiment of the invention, and FIGS. 2, 3, and 4 are the - line in FIG. FIG. 5 is a cross-sectional view showing a conventional planetary gear device. DESCRIPTION OF SYMBOLS 1... Support pin, 2... Planet gear, 8... Sun gear, 10... Front machine frame, 11... Internal gear device, 11a... Internal gear, 11b... Rim part, 1
2, 14...Rib, 13...Protrusion, 15...Concave groove, 16...Columnar space, 17...Elastic material, 18...
Projection, 19...flange, 25...motor shaft,
27 is a concave groove. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Scope of utility model registration request] In internal reduction starters that have a built-in planetary gear between the armature rotating shaft and the output rotating shaft that has a pinion geared to the ring gear of the engine, the internal gear of the planetary gear is made of synthetic resin molded material. At the same time, an annular elastic body is fitted between the outer periphery of the opening of the internal gear and the machine frame, and the annular elastic body is provided to protrude in the axial direction at several locations on the circumference, thereby creating a protrusion. and the protrusion is fitted into a columnar space formed by opposing a rib provided on the outer periphery of the internal gear and a rib provided on the inner periphery of the machine frame. A planetary gear type internal reduction starter that is characterized by: